Preparation of cellulose 2-methylstilbene-5-carboxylate and photoregulation of its properties

Abstract

As a photofunctional material, cellulose 2-methylstilbene-5-carboxylate (MSB-cellulose) was prepared by the reaction of microcrystalline cellulose with 2-methylstilbene carbonyl chloride, and photoregulation of some properties of the MSB-cellulose under irradiation with UV light was investigated. The 2-methylstilbene moieties in the MSB-cellulose undergo reversible isomerization from the trans, to the cis form under irradiation with UV light of λ > 290 nm and from the cis to the trans, form with λ≈ 250 nm, although the latter isomerization was not complete. Regulation of the swelling ability of MSB-cellulose in water and in benzene was examined under UV irradiation. The swelling ability in water was found to increase under UV irradiation with λ > 290 nm and to decrease with λ≈ 250 nm. The swelling ability in benzene decreased under UV irradiation with λ, > 290 nm and increased with λ≈ 250 nm. The degree of change in the swelling ability in benzene under alternate irradiations with the two wavelengths was found to decrease only slightly even after five cycles of irradiations.